The GetDeb.net website has not been updated for Ubuntu 10.04 yet, however the GetDeb repository is already available for Ubuntu 10.04 Lucid Lynx users. There are not a lot of packages available for now, but more should be updated soon:
The getdeb repository for lucid was created past weekend, a few packages have been already uploaded.
I think we should focus on having a significant number of packages available for lucid on the 29th, even if that means stopping testing/publishing for 9.10 right now.
(João Luís Marques Pinto, GetDeb Team Leader)
To add the GetDeb.net repository in Ubuntu 10.04 Lucid Lynx, simply paste this in a terminal:
sudo bash -c "echo 'deb http://archive.getdeb.net/ubuntu lucid-getdeb apps' >> /etc/apt/sources.list"
wget -q -O- http://archive.getdeb.net/getdeb-archive.key | sudo apt-key add -